Complex compound of metals with aliphatic polyhydroxy-carboxylic acids and process of making the same



Patented June 26, 1934 COMPLEX COMPOUND OF METALS WITH ALIPHATICPOLYHYDROXY-CARBOXYLIC ACIDS AND PROCESS OF MAKING THE SAME WilhelmTraube and Fritz Kuhbier, Berlin, Germany, assignors to WinthropChemical Company, Inc., New York, N. Y., a corporation of New York NoDrawing. Application December 14, 1931, Serial No. 581,049. In GermanyMarch 21,

32 Claims. (Cl. 260-11) The present invention relates to aprocess ofpreparing metal complex compounds of aluminium, trivalent iron,trivalent chromium, antimony and bismuth with aliphatic polyhydroxycarboxylic acids and to the basic alkaline-earth metal salts of thesecomplex compounds being intermediate products in the said process.

Metal complex compounds, for instance of aluminium, trivalent iron andantimony have already been prepared.

The present invention provides a process to obtain metal complexcompounds of aliphatic polyhydroxy carboxylic acids from their aqueoussolutions in a pure, uniform state by Way of the basic alkaline-earthmetal salts of the said metal complex compound being insoluble orsparingly soluble in water.

In accordance with the present invention complex compounds of aluminium,trivalent iron, trivalent chromium, antimony and bismuth, which metalshave proved equivalent in the process of our present invention, areprepared by first producing basic alkaline-earth metal salts beinginsoluble or sparingly soluble in water by precipitating these salts bythe addition of an alkalineearth metal salt or hydroxide to an aqueousalkaline solution containing an aliphatic polyhydroxy carboxylic acid towhich one of the metals above specified is linked in a complex likelinkage, said aqueous alkaline solutions being prepared by the action ofa salt or hydroxide of the metals specified on an alkaline solution ofthe aliphatic polyhydroxy carboxylic acid. The basic alkaline-earthmetal salts of the metal complex compounds thus obtained in a uniformstate are further transformed into their water-soluble alkali-,ammcniumor amine salts by double decomposition with alkali-, ammoniumoramine salts of such acids which yieldwith alkaline-earth metal ionssalts insoluble or sparingly soluble in water.

It may be mentioned that the basic alkalineearth metal salts of themetallic complex compounds may further be transformed into thecorresponding water-soluble neutral alka1ine-earth metal salts byreacting thereupon with about 1 mol of the complex forming aliphaticpolyhydroxy carboxylic acid.

When using in our new process, for instance, an aqueous alkalinesolution of ferric-gluconate,

the formation of the basic barium salt proceeds in accordance with thefollowing probable equation:

CsI-I1207+ FeCls +BaC12 5NaOH= Csl-l'zO'zFeBa 5NaCl 5H20.

When transforming the above basic barium salt into the correspondingwater-soluble sodium salt the process proceeds probably for instanceaccording to the following equation:

CeHvOvFeBa +NaI-ISO4=CsHsO7FeNa+BaSO4.

The above formula correspond to the result of the analysis.

More graphic formulae would probably be for the basic barium salt theformula:

which may be further explained by the following structural formula:

Fe for the sodium salt-the formula:

Na [O2CeHe (OH) zOsFe] aq.,

which may be further explained by the following structural formula:

CHH.CH.CH.OHOH.OHOH.C O ONa aq.,

Fe for the neutral barium salt the formula:

which may be further explained by the following structural formula:

Ba aq.,

As is to be seen from the above formulae, we presume that thealkaline-earth metal cation substitutes in the insoluble alkaline-earthmetal salts, which have been called basic salts, one hydrogen atom ofthe carboxylic group and another hydrogen atom of a hydroxyl group ofthe polyhydroxy carboxylic acid; however, in the alkali andalkaline-earth metal salts, which have been called neutral salts, thealkali-, alkalineearth metal cation respectively, substitute only thehydrogen atom of the carboxylic group.

In a similar manner as described above for the production and furthertransformation of the basic barium ferric-gluconate the process proceedswhen using instead of gluconic acid other aliphatic polyhydroxycarboxylic acids and instead of the iron complex compound thecorresponding complex compounds of aluminium, trivalent chromium,antimony and bismuth; further instead of a barium salt or bariumhydroxide a calciumor strontium salt or hydroxide may be employed. Ascomplex forming polyhydroxy carboxylic acids further may be used, forinstance, glyceric-, tartaric-, arabic-, mucic-, saccharic,glucoheptonic-, mannoheptonic, lactobionicacid and the like. As is to beseen from the above formulae in our metal complex compounds about oneatom of. aluminium, trivalent iron, trivalent chromium, antimony orbismuth is contained in one molecule of the complex forming hydroxycarboxylic acid and one alkali or alkaline-earth metal atom is boundchiefly by the carboxylic group. This result is in general obtained whenreacting upon one mol of the polyhydroxy carboxylic acid with about onemol of a salt or hydroxide of one of the metals specified and addingabout one mol of the alkaline-earth metal compound to the solutionobtained in order to precipitate the insoluble basic alkaline-earthmetal salt. Also in such cases where dicarboxylic acids are employedsometimes no more of the alkaline-earth metal compound is required forthe precipitation of the insoluble basic salt. In general, of course, itis advantageous to use a water-soluble alkaline-earth metal salt orhydroxide when precipitating the metal complex compounds as basicalkaline-earth metal salts.

Our new process is advantageously performed by reacting upon an aqueousalkaline solution of the aliphatic polyhydroxy carboxylic acid withabout 1 mol of a salt or hydroxide of aluminium, trivalent iron,trivalent chromium, antimony or bismuth and then adding about 1 mol of asalt or hydroxide of an alkaline-earth metal. The basic alkaline-earthmetal salt of the metallic complex compound precipitated is separatedfrom the liquid. In order to transform it into a water-soluble productit is decomposedin an aqueous suspension while shaking or stirring withan equivalent quantity of an alkali metal, ammonium or amine salt of anacid which forms water-insoluble salts with alkaline-earth metal ions,for example, with alkali metal ammonium or amine sulfates, bisulfates,carbonates, bicarbonates or oxalates. When the whole quantity of thealkaline-earth metal present in the mixture is transformed into thewater-insoluble alkalineearth metal salt, the latter salt is separatedfrom the mixture. From the filtrate the alkali metal, ammonium or aminesalt of the metallic complex compound produced may be obtained byevaporating or by precipitating by means of alcohol.

As alkali metal, ammonium or amine salts for the decomposition of thebasic alkaline-earth metal salts of the metallic complex compoundpreferably the salts of the sulfuric, carbonic and oxalic acid, forexample, sodium and potassium sulfate, bisulfate, carbonate,bicarbonate, oxalate or bioxalate, or the corresponding salts ofammonia, diethylamine, triethylamine, diethylaminoethanol,ethylenediamine and the like have proved suitable.

The water-insoluble basic alkaline-earth metal salts of the metalliccomplex compounds may, as already mentioned, further be transformed intowater-soluble products by reacting upon the said basic salts with aboutone equivalent of the aliphatic polyhydroxy carboxylic acid used ascomplex forming component in the complex compound. The neutralwater-soluble alkaline-earth metal salt of the metallic complex compoundthus produced may be separated from the solution by evaporating orprecipitating by means of alcohol.

The reaction, in general, performs at room temperature, however,sometimes heating is of advantage. Of particular value we consider theproduction, according to our new process, of the complex compounds ofiron, antimony and bismuth, preferably the sodium salts of such ones, ascontain a polyhydroxy carboxylic acid derived from hexane as complexforming component, especially gluconic acid.

The products obtainable in accordance with our invention may be usedpreferably for medicinal purposes, but they may also be employed for thegeneral technical use.

The following examples illustrate our invention without restricting itthereto, the parts being by weight.

Example 1.To a solution of 4.2 parts of ferric-chloride (1 mol) in '70parts of water 5 parts of gluconic acid and 42.5 parts of a 12% solutionof caustic soda possibly free from carbonate (5 mols) are added. Themixture is then treated with a concentrated aqueous solution of 6.2parts of crystallized barium chloride (1 mol),

whereby a yellow precipitate of barium-ferricgluconate of the formulaCsHqovFeBa. aq. separates.

When treating a solution of ferric chloride, gluconic acid and causticsoda prepared in accordance with the above directions with a conif.

centrated aqueous solution of 2.8 parts of calcium chloride (free fromwater) the basic calciumferric-gluconate of the formula CsHqO7FeCa. aq.is obtained. In order to obtain a very good yield of this salt. it isnecessary to heat the solution ii-t;

the calcium salt but in suitably chosen other proportionscalcium-ferric-gluconates of another composition, for instance, a saltcontaining upon 2 molecules of gluconic acid 1 atom of iron and 2 atomsof calcium and having accordingly the formula C12I-lmO14CazFe, and afurther salt, containing upon 4 molecules of gluconic acid 3 atoms ofiron and 6 atoms of calcium are obtainable.

The described barium and calcium salts may be transformed intowater-soluble compounds in the following manner:

Basic barium-ferric-gluconate is made into an even paste with about thesame quantity of water.

After cooling to the mixture so much of a concentrated potassiumbisulfate solution is added as is required for the transformation of allbarium into barium sulfate. When the decomposition is complete themixture is centrifuged from the barium sulfate. A concentrated solutionof the neutral postassium-ferric-gluconate containing upon 1 molecule ofthe acid 1 atom each of potassium and iron is thus obtained. The salt isseparated from the solution by the addition of amine-bisulfatesolution).

alcohol. It has the probable formula:

K[O2C6Hs(OH) 2.03F8] aq.,

and accordingly probably the following structural formula:

({3H2.CH.OH.OH.CH.COOK. aq.

O OH H Alternatively, the basic barium-ferric-gluconate may betransformed into a water-soluble compound by making into a paste withsome water and decomposing in the same manner as indicated above withthe equivalent quantity of ammonium bisulfate. The solution, separated 1from the barium sulfate formed, is evaporated in vacuo. Theammonium-ferric-gluconate obtained in this manner is readily soluble inwater with neutral reaction. It is a yellow powder containing upon 1molecule of the acid 1 atom of iron and one ammonium group. It has theprobable formula: NH4[O2CsHs(OH)2.03FB13CL, and accordingly probably thefollowing structural formula:

CH2.OH.CH.CH.CH.C O ONH4.aq.

O O H OH The neutral dimethylamine-ferric-glueonate is l V obtained when8 parts of the basic barium-ferric- V barium sulfate from the filtrate,the neutral magnesium-ferric-gluconate readily soluble in water may beisolated by precipitation with alcohol. According to the analysis it iscomposed according to the formula: (Cel-lsovFelzMg-l-HzO.

The basic barium-ferric gluconate may further be transformed into awater-soluble compond in the following manner:

Into a concentrated aqueous solution containing about -30% of gluconicacid basic bariumferric-gluconate is introduced in small portions untilthe acid reaction of the liquid has disappeared. The iormed salt atfirst readily dissolves on stirring. In order to dissolve the rest,gentle heating of the liquid is required. From the finally resultingviscous solution a precipitate of neutral barium-ierric-gluconateseparates on the addition of alcohol, which readily changes to a powderon kneading. It contains upon 2 molecules of gluconic acid 1 atom eachof iron and barium and corresponds to the probable formula:

Ba [C1zH19O1-1Fe] aq., and probably to the following structural formula;

omoncnon-o H.CH-OH.C oomoo (105111105. aq.

When decomposing this soluble barium salt with calcium sulfate thecorresponding calcium-ferricgluconate is obtained according to thefollowing equation:

The basic calcium-ferric-gluconate of the formula: ChzHwOnCazFe, abovementioned is transformed into a soluble compound in the followingmanner: 2

To a concentrated aqueous solution of 2- molecules of gluconic acid 1molecule of the basic calcium-ferric-gluconate is added in smallportions. It dissolves without leaving a residue when finely ground andgently heated. Alcohol precipitates from the solution thus obtained alight yellow salt, readily soluble in water with neutral reaction,containing upon 4 molecules of gluconic acid 2 atoms of calcium and 1atom of iron. It has the probable formula Example 2.-1 part of mucicacid is dissolved in parts of a '7-8% aqueous solution of caustic sodaand to this solution 2.6 parts of a 67% aqueous ferric chloride solutionare added. When adding to the liquid a solution of 0.5 parts of bariumchloride in 10 parts of water a white precipitate appears temporarily.The clear solution when heated to boiling, separates a durable whitishprecipitate. The mixture is kept boiling for some time and theprecipitate is sucked off while hot and washed first with hot water,then with alcohol and ether. The air-dried compound according to theanalysis corresponds to the formula When using instead of mucio acid inthe above example corresponding quantities of, for instance, saccharicor galaetoni'c acid, the corre- 'sponding complex compounds with similarproperties are obtained.

. Example 3.2 parts of gluconic acid,'22 parts of a 12% aqueous solutionof caustic soda free from carbonate and 3.1 parts of bismuth chlorideare mixed together in order to obtain an alkaline solution containingbismuth This solution is dropped into a heated and continually stirredsolution of 2.4 parts of barium chloride in parts of water. Thebarium-bismuth-gluconate precipitating is separated from the liquid bysuction. It is in the dry state a white powder insoluble in water. Theyield amounts to 50-60%.

From the above insoluble basic salt a watersoluble product is obtainedin the following manner:

Into a concentrated aqueous solution of gluconic acid so much of thedifiicultly soluble basic barium-bismuth-gluconate is introduced whilegently heating as is dissolved by the solution. The solution obtained,if necessary after filtration, is poured into alcohol, whereby a solublebarium-bismuth gluconate separates, which con tains the double quantityof gluconic acid than the difiicultly soluble salt.

Example 4.-Into a boiling solution of 6 parts of gluc'onic acid in 45parts of a 13% aqueous caustic soda solution 4.3 parts of antimonytrioxide are introduced in small portions. When the antimony trioxidehas been dissolved the solution is cooled and mixed with a solution of7.2 parts of crystallized barium chloride in 25 parts of water. Therebytemporarily a precipitate appears, but afterthe addition of thewholequantity of the barium chloride the solution becomes completelyclear.. On heating the solution to boiling the basicbarium-antimony-gluconate separates in form of a white crystallineprecipitate. It is sucked off while hot, since the pre-' cipitatedissolves again on cooling of the solution. Before separating theprecipitate from the liquid, the latter is kept boiling for some time.The precipitate remaining on the filter is washed with hot water, thenwith alcohol and acetone and dried on an unglazed burned clay plate.According to the analysis the basic barium-antimony-gluconate has theformula:

CsHvOvSbLBa-l- 3H2O.

CizI-ImOrrSbaCzHsNz aq.

separates. It is readily soluble in water.

When using instead of ethylenediamine sulfate sodium sulfate thesodium-antimony-gluconate of the probable formula: CeHsO7SbNa-l-aq. isobtained.

In a similar manner instead of antimony trioxide, antimonic acid may beused for preparing the antimony complex compounds. When, for example,antimonic acid is dissolved in an alkaline solution of gluconic acid andcaustic soda and the solution is mixed with a barium chloride solution,a whitish powder separates, which may be isolated in the usual manner.

Example 5.-A concentrated aqueous solution of one part of gluconic acidis mixed with a solution of 1.4 parts of crystallized chromic chloride(containing crystal water) and then, while well shaking, with 8 parts ofan about 13% aqueous caustic soda solution; The resulting clear greensolution is diluted with some water. Thereto a solution of 1.2 parts ofbarium chloride in some water is added. Thereby thebasicbarium-chromic-gluconate separates in form of a fine-crystalline greenprecipitate. After heating to boiling the precipitate is sucked off,washed with water, alcohol and acetone and driedon an unglazed'burnedclay plate. The compound has the formula:

In order to transform the Water-insoluble basic barium-chromic-gluconateinto the water-soluble neutral barium-chromic-gluconate, 2 parts .of theformer salt are dissolved in a concentrated aqueous solution of about0.9-1.0 parts of gluconic acid while gently heating. From the clearsolution obtained alcohol precipitates the neutral water-solublebarium-chromic-gluconate of the formula:

Example 6.-To a concentrated aqueous solution of 2 parts of gluconicacid a solution of 2.4 parts of crystallized aluminium chloride andwhile well shaking a solution of 2' parts of caustic soda in 15 parts ofwater are added. The clear solution is then mixed with a concentratedaqueous solution of 2.4 parts of crystallized barium chloride. Therebythe basic barium-aluminium-gluconate separates in form of white finecrystals. The precipitate is sucked off, washed with water, alcohol andacetone and dried on an unglazed burned clay plate. The new compound hasthe formula:

In order to transform the water-insoluble basicbarium-aluminium-gluconate into a neutral water-soluble salt, 10 partsof the former salt are made into a paste with 6 parts of water. Aftercooling to 6 C. the paste is mixed with so much of a concentratedaqueous solution of tetraethylammonium-bisulf ate as is required for theprecipitation of the barium in the form of barium sul-' fate. Thefiltrate from the barium sulfate is evaporated to dryness, whereby theneutral tetraethylammonium-aluminium-gluconate of the formula:

remains. The new compound is hygroscopic and readily soluble in Waterand alcohol.

' While we have described our invention in great detail and with respectto preferred embodiments thereof, We do not desire to limit ourselves tosuch details or embodiments, since many modifications and changes may bemade and the invention embodied in widely different forms withoutdeparting from the spirit or scope of the invention in its broadestaspects. Hence we desire to cover all modifications and forms within thescope or language of any one or more of the appended claims. 1

We claim:

1. In the process of preparing metal complex compounds the; steps whichcomprise precipitating from an aqueous solution of an alkali metal saltof. an aliphatic polyhydroxy carboxylic acid to which a metal of thegroup consisting of aluminium, trivalent iron, trivalent chromium,antimony and bismuth is linked in complex like linkage, said solutioncontaining alkali metal hydroxide, by the addition of an alkaline-earthmetal compound selected from the group consisting of the water-solublesalts and the hydroxides thereof the basic alkaline-earth metal salt ofthe metal complex compound.

2. In the process of preparing metal complex compounds the steps whichcomprise precipitating from an aqueous solution of an alkali metal saltof a polyhydroxy carboxylic acid derived from hexane to which a metal ofthe group consisting of aluminium, trivalent iron, trivalent chromium,antimony and bismuth is linked in complex like linkage, said solutioncontaining alkali metal hydroxide, by the addition of an alkaline-earthmetal compound selected from the group consisting of the water-solublesalts and the hydroxides thereof the basic alkaline-earth metal salt ofthe metal complex compound.

3. In the process of preparing complex compounds the steps whichcomprise precipitating from an aqueous solution of an alkali metal saltone mol of an aliphatic polyhydroxy carboxylic acid to which 1 gram atomof a metal selected from the group consisting of trivalent iron,antimony and bismuth is linked in complex like linkage, said solutioncontaining alkali metal hydroxide by the addition of about 1 mol of awatersoluble alkaline-earth metal compound selected from the groupconsisting of the water-soluble salts and the hydroxides thereof thebasic alkaline-earth metal salt of the metal complex compound.

4. In the process of preparing metal complex compounds the steps whichcomprise precipitating from an aqueous solution of an alkali metal saltof 1 mol of a polyhydroxy carboxylic acid derived from hexane to whichone gram atom of a metal selected from the group consisting of trivalentiron, antimony and bismuth is linked in complex like linkage, saidsolution containing alkali metal hydroxide, by the addition of about 1mol of a water-soluble alkaline-earth metal compound selected from thegroup consisting of the water-soluble salts and the hydroxides thereofthe basic alkaline-earth metal salt of the metal complex compound.

5. In the process of preparing metal complex compounds the steps whichcomprise precipitating from an aqueous solution of an alkali metal saltof 1 mol of a polyhydroxy mono-carboxylic acid derived from hexane towhich one gram atom of a metal selected from the group consisting oftrivalent iron, trivalent antimony and bismuth is linked in complex likelinkage, said solution containing alkali metal hydroxide, by theaddition of about 1 mol of a water-soluble calcium salt the basiccalcium salt of the metal complex compound.

6. In the process of preparing ferric complex compounds the steps whichcomprise precipitating from an aqueous solution of an alkali metal saltof one mol of gluconic acid to which one gram atom of trivalent iron islinked in complex like linkage, said solution containing alkali metalhydroxide, by the addition of about 1 mol of a water-soluble calciumsalt the basic calcium salt of the ferric complex compound.

7. In the process of preparing antimony complex compounds the stepswhich comprise precipitating from an aqueous solution of an alkali metalsalt of one mol of a polyhydroxy monocarboxylic acid derived from hexaneto which one gram atom of trivalent antimony is linked in complex likelinkage, said solution containing alkali metal hydroxide, by theaddition of about one mol of a water-soluble barium salt the basicbarium salt of the antimony complex compound.

8. In the process of preparing antimony complex compounds the stepswhich comprise precipitating from an aqueous solution of an alkali metalsalt of one mol of gluconic acid to which one gram atom of trivalentantimony is linked in complex like linkage, said solution containingalkali metal hydroxide, by the addition of about one mol of aWater-soluble barium salt the basic barium salt of the antimony complexcompound.

9. In the process of preparing bismuth complex compounds the steps whichcomprise precipitating from an aqueous solution of an alkali metal saltof one mole of a polyhydroxy mono-carboxylic acid derived from hexane towhich one gram atom of bismuth is linked in complex like linkage, saidsolution containing alkali metal hydroxide, by the addition of about onemol of a water-soluble barium salt the basic barium salt of the bismuthcomplex compound.

10. In the process of preparing bismuth complex compounds the stepswhich comprise precipitating from an aqueous solution of an alkali metalsalt of one mol of gluconic acid to which one gram atom of bismuth islinked in complex like linkage, said solution containing alkali metalhydroxide, by the addition of about one mol of a Water-soluble bariumsalt the basic barium salt of the bismuth complex compound.

11. The process which comprises precipitating from an aqueous solutionof an alkali metal salt of an aliphatic polyhydroxy carboxylic acid towhich a metal of the group consisting of aluminium, trivalent iron,trivalent chromium, antimony and bismuth is linked in complex likelinkage, said solution containing an alkali metal hydroxide, by theaddition of an alkaline-earth metal compound selected from the groupconsisting of the water-soluble salts and the hydroxides thereof thebasic alkaline-earth metal salt of the metal complex compound,separating the basic salt, causing it to react in aqueous suspensionwith at least an equivalent of a salt selected from the group consistingof alkali metal ammonium and amine salts the anion of which salt formswith alkaline-earth metal ions salts difiicultly soluble in water andseparating the insoluble precipitate formed.

12. The process which comprises precipitating from an aqueous solutionof an alkali metal salt of a polyhydroxy carboxylic acid derived fromhexane to which a metal of the group consisting of aluminium, trivalentiron, trivalent chromium, antimony and bismuth is linked in complex likelinkage, said solution containing alkali metal hydroxide, by theaddition of an alkaline-earth metal compound selected from the groupconsisting of the water-soluble salts and the hydroxides thereof thebasic alkaline-earth metal salt of the metal complex compound,separating the basic salt, causing it to react in aqueous suspensionwith at least an equivalent of a salt selected from the group consistingof alkali metal, ammonium and amine salts the anion of which salt formswith alkaline-earth metal ions salts difficultly soluble in water andseparating the insoluble precipitate formed.

13. The process which comprises precipitating from an aqueous solutionof an alkali metal salt of one mol of an aliphatic polyhydroxycarboxylic acid to which one gram atom of a metal selected from thegroup consisting of trivalent iron and antimony is linked in complexlike linkage, said solution containing alkali metal hydroxide, by theaddition of about one mol of a water-soluble alkaline-earth metalcompound selected from the group consisting of the water-soluble saltsand the hydroxides thereof the basic alkaline-earth metal salt of themetal complex compound, separating the basic salt, causing it to reactin aqueous suspension with at least an equivalent of a salt selectedfrom the group consisting of alkali metal, ammonium and amine salts'theanion of which salt forms with alkaline-earth metal ions saltsdifiicultly soluble in water and separating the insoluble precipitateformed.

14. The process which comprises precipitating from an aqueous solutionof an alkali metal salt of one mol of a polyhydroxy carboxylic acidderived from hexane to which one gram atom of a metal selected from thegroup consisting of trivalent iron and antimony is linked in complexlike linkage, said solution containing alkai metal hydroxide, by theaddition of about one mol of a water-soluble alkaline-earth metalcompound selected from the group consisting of the watersoluble saltsand the hydroxides thereof the basic alkaline-earth metal salt of themetal complex compound, separating the basic salt, causing it to reactin aqueous suspension with at least an equivalent of a salt selectedfrom the group consisting of alkali metal, ammonium and amine salts theanion of which salt forms with alkalineearth metal ions salts dimcultlysoluble in water and separating the insoluble precipitate formed.

15. The process which comprises precipitating from an aqueous solutionof an alkali metal salt of one mol of a polyhydroxy mono-carboxylic acidderived from hexane to which one gram atom of trivalent iron is linkedin complex like linkage, said solution containing alkali metalhydroxide, by the addition of about one mol of a water-soluble calciumsalt the basic calcium salt of the ferric complex compound, separatingthe basic calcium salt, causing it to react in aqueous suspension withat least an equivalent of an alkali metal sulfate and separating thecalcium sulfate formed.

16. The process which comprises precipitating from an aqueous solutionof an alkali metal saltof one mol of gluconic acid to which one gramatom of trivalent iron is linked in complex like linkage, said solutioncontaining alkali metal hydroxide, by the addition of about one mol of awater-soluble calcium salt the basic calcium salt of the ferric complexcompound, separating the basic calcium salt, causing it to react inaqueous suspension with at least an equivalent of an alkali metalsulfate and separating the calcium sulfate formed.

17. The process which comprises precipitating from an aqueous solutionof an alkali metal salt of one mol of a polyhydroxy mono-carboxylic acidderived from hexane to which one gram atom of trivalent antimony islinked in complex like linkage, said solution containing alkali metalhydroxide, by the addition of about one mol of a water-soluble bariumsalt the, basic barium salt of the antimony complex compound, separatingthe basic barium salt, causing it to react in aqueous suspension with atleast an equivalent of an alkali metal sulfate and separating the bariumsulfate formed.

18. The process which comprises precipitating from an aqueous solutionof an alkali metal salt one mol of gluconic acid to which one gram atomof trivalent antimony is linked in complex like linkage, said solutioncontaining alkali metal hydroxide, by the addition of about one mol of abarium salt the basic barium salt of the antimony complex compound,separating the basic salt, causing it to react in aqueous suspensionwith at least an equivalent of an alkali metal sulfate and separatingthe barium sulfate formed.

19. A basic alkaline-earth metal salt of a metal complex compoundwherein a metal of the group consisting of aluminium, trivalent iron,trivalent chromium, antimony and bismuth is linked in a complex likemanner to an aliphatic polyhydroxy mono-carboxylic acid, said salt beingdiflicultly soluble in water.

20. A basic alkaline-earth metal salt of a metal complex compoundwherein a metal of the group consisting of aluminium, trivalent iron,trivalent chromium, antimony and bismuth is linked in a complex likemanner to a polyhydroxy monocarboxylic acid derived from hexane, saidsalt being difiicultly soluble in water. r

21. A basic alkaline-earth metal salt of a ferric complex compoundwherein one atom of trivalent iron is linked in a complex like manner toone molecule of an aliphatic polyhydroxy carboxylic acid, said saltbeing difiicultly soluble in water.

22. A basic alkaline-earth metal salt of a ferric complex compoundwherein one atom of trivalent iron is linked in a complex like manner toone molecule of a polyhydroxy carboxylic acid derived from hexane, saidsalt being diificultly soluble in water.

23. A basic calcium salt of a ferric complex compound wherein one atomof trivalent iron is linked in a complex like manner to one molecule ofa polyhydroxy mono-carboxylic acid derived from hexane, said salt beingdifiicultly soluble in water.

24. The basic calcium salt of ferric gluconate wherein one atom oftrivalent iron is linked in a complex like manner to one molecule ofgluconic acid, said salt being diflicultly soluble in water.

25. Basic alkaline-earth metal salts of antimony complex compoundswherein one atom of antimony is linked in a complex like manner to onemolecule of an aliphatic polyhydroxy monocarboxylic acid, said saltsbeing difiicultly soluble in water.

26. Basic alkaline-earth metal salts of antimony complex compoundswherein one atom of antimony is linked in a complex like manner to apolyhydroxy carboxylic acid derived from hexane, said salts beingdifficultly soluble in water.

27. Basic barium salts of antimony complex compounds wherein one atom oftrivalent antimony is linked in a complex like manner to one molecule ofa polyhydroxy mono-carboxylic acid derived from hexane, said salts beingdifficultly soluble in water.

28. The basic barium salt of antimony gluconate wherein one atom oftrivalent antimony is linked in a complex like manner to one molecule ofgluconic acid, said salt being diflicultly soluble in water.

29. Basic alkaline earth metal salts of bismuth complex compoundswherein one atom of bismuth is linked in a complex like manner to onemolecule of an aliphatic polyhydroxy carboxylic acid, said salts beingdifficultly soluble in water.

30. Basic alkaline-earth metal salts of bismuth complex compoundswherein one atom of bismuth is linked in a complex like manner to onemolecule of a polyhydroxy carboxylic acid derived from hexane, saidsalts being diflicultly soluble in water.

31. Basic barium salts of bismuth complex compounds wherein one atom ofbismuth is linked in a complex like manner to one molecule of apolyhydroxy mono-carboxylic acid derived from hexane, said salts beingdifilcultly soluble 5 in water.

32. The basic barium salt of bismuth gluconate wherein one atom ofbismuth is linked in a complex like manner to one molecule of gluconicacid, said salt being difiicultly soluble in water. a

W'ILHELM TRAUBE. FRITZ KUHBIER.

